Impact tool



I f/prl 7, 1964 c. B. slEBER 3,127,941

IMPACT TOOL4 Filed Oct. 18, 1960 2 Sheets-Sheet 1 April 7, 1954 c. B.slEBr-:R 3,127,941

IMPACT'TOOL Filed Oct. 18, 1960 2 Sheets-Sheet 2 fl I gi' Cgi @5226921 ii 70 m nwrm-r United States Patent O 3,127,941 IMPACT TOUL Charles B.Sieber, 17 W. 514 Riardon Road, Villa Park, lll. Filed Get. 18, 1960,Ser. No. 63,356 9 Claims. (El. 1'73 98) My invention relates to animpact tool ywhich may be used in various combinations for delivering -aseries of impact blows on a chisel such as is used in a demolition tool,a riveting tool, or may be embodied in a tool for removing dents insheet metal such 'as automobile bodies, and the like.

Another object of my invention is the provision of an impact tool 'whichis comparatively light in weight and can be easily moved and handled inuse, and which can be easily actuated by an elect-ric, air, hydraulic,or gasoline motor or irom a power line or any other suitable source ofpower, making possible the use of the tool in any place lwhere the usualelectric current is available.

Another and further object of my invention is the provision of an impacttool which is easily handled and does not possess the vibration .commonin air operated demolition tools which is an objection to the use ofsuch tools yboth in handling and operation because of the necessity ofsupplying air under .pressure for lthe operation of the tools.

Another and further object of my invention is the provision of a tool inwhich a greater number of impact blows can he delivered than is normally.possible in tools of this type and character and is an improvement uponthe impact tool claimed and described in Patent No.` 2,888,246 issued tome as of May 26, 1959.

These and other objects of my invention will be further and betterunderstood by reference to the accompanying drawings in whlich FIG. 1 isa view partially in elevation and partially in section of my improvedtool taken on line d 1 of FIG. 2;

FIG. 2 is a View partially in section and partially in elevation `online 2 2 of FIG. 1;

FIG. 3 is a sectional View of a part of the tool taken on line 3 3 ofFIG. 4;

FIG. 4 is a Vertical rsectional View showing a portionof the housing andoperating mechanism taken on line 4 4 of FIG. 3;

FIG. 5 is a vertical sectional view showing a portion of the housing andoperating par-ts taken on line 5 5 of FIG. 4;

FIG. 6 isl an exploded View in perspective of one of the springs used inconnection with the operation of the striking wheel in the tool.

Referring now specically to the drawings in which like referencecharacters refer to like parts throughout, a main housing 1t) is shownwhich has a motor casing 11 secured thereto Kbyl means of Ibolts 12, 12with the housingV having openings at each of its sides which are' closedby cheek plates I3 and 14, and which are secured -to the main housing10' by means of bolts 15, 15 which provide a complete housing mechanismfor the rrain operating parts of the tool.

A striking Iwheel 16 is provided which is preferably machined from asingle piece of metal and comprises a rim portion' 17 with an arcuatechannel |18 formed therein and Lhavin-g a central web portion 'with stubaxles 19 and 2i), extending outwardly therefrom and integrally formedtherewith, whichY axles `19 and Zit are mounted in bearings 2li, 21fixed in the cheek plates 13 and 14 respectively, and within which theaxles 19 and Ztl orrning ay part of the striking wheel 16 rotates. l Apair of belt wheels 22 and 23 are provided which belt wheels com-3,127,941 Patented Apr. 7, 1964 ICC prise rirn port-ions 24, webportions 25, and hub portions 26, which have ring 'bearings 27, 27mounted therein and through which the stnb axles 19 and 20 extend so thebelt wheels 23 and 24 rotate freely upon the axles 19 and 20. The rimportions 2l4- and hub portions 26 of the wheels 2,2 and 23 extend in thesame direction to one side lfrom their web portions 25 so that openrecessed circular faces are provided for the wheels 22 and 23 adjacenteach side of 4the stniking wheel 16.

Sp-irally wound .torsion springs 28 and 29 are mounted within therecessed circular faces of the wheels 22 and 23 respectively and aresecu-red at one lof their ends to the striking wheel 16 and at theirother ends to the belt wheels 22 and 2.3 respectively, one :of whichsprings 28, in exploded form, is shown in FIG. 6. Plhe' spring 2Scomprises a single piece of tempered wire having an internal .coil 30wound about the hub 26 of the wheel 22 and extending through an opening3l in `a thin circular separator plate 32 with the end portions of thecoil 30 merging into another :coil adjacent thereto of -a slightlygreater radii and extending in a counter-clockwise direction andcontinuing outward in the form of `other coils in a constant increasingradii to one end 33 of the spring 28, thereby producing a section A ofIthe spring 28 with the end 33 being .anchored in the rim portion 17 ofthestriking wheel 16 with all of the coils compris-ing the section Abeing in 1the same plane and compressed in the space between the plate32 and the side of the striking wheel 16 to the end 33 of the spring 2'8is attached. The opposite end portion of the coil 30 merges into otherycoils which extend in a counter-clockwise direction with a constantlyincreasing radii forming a section B of the spring 28 with the end coilhaving an end 34 which is anchored in the side of the web 25 of the4belt wheel 2x2' adjacent the rim portion 24 with all .of the coils ofsection B being in the same .plane and confined in the circular spacebetween the plate 32 and the web 2S of the -belt wheel 22. It will bethus understood that the spring 28 consists of two co-planar portions Aand B- of constantly increasing radii yfrom the center coil 30, bothportions A and B having their coils exending in a clockwise directionwhen seen in line 5 5 of FIG. 4.

The spring 29 is constructed like the spring Z8 but in a reversedirection with co-planar sections, with an end 35 anchored in the web 25of the wheel 23 adjacent thev rim 24 and wound in a` circular clockwisedirection towards a constantly decreasing radii to a central coil 36 inthe same plane, which central coil 36 is diagonally disposed merginginto an adjacent coil in a different plane' of an increased radii andcontinues outward therefrom in a constantly increasing radii terminatingin an end 37 which is anchored in the side of the rim portion 17 of thestriking wheel 16 so that rotary movement of they belt wheel 23 istransferred to the striking wheel 16. A plate 32 is placed between thecoplanar sections of the spring 29 into the coil 36 extending throughthe central opening 31 in the plate 32. The spring 29 therefore occupiesthe space in the face of the belt wheel 23 and exerts force upon thestriking wheel 16 in a counter-clockwise direction when looking at thewheel 16 in the directionv of line 5 5 of FIG. 4'.

A single spiral spring such as is shown in Patent' No. 2,888,246 hereinalso referred to may be used instead of the doublespring shown herein,in which case oneend of the spring would be secured to the wheel 16 nearthe outer periphery thereof and the other end to the hub 26 of the beltwheel or to the web portions of the belt wheels, as may be preferred.

The motor casing 11 has an electric motor mounted therein having a motorshaft 38 extending therefrom upon which' a bevel gear wheel 39 ismounted which is in mesh with a second bevel gear 40 fixed on a shaft 41mounted in a sub frame 42 iixed to the housing 10 in any approvedmanner. Belt wheels 43, 43 are mounted on the outer ends of the shaft 41and have endless belts 44, 44 thereon which operate on the belt wheels43, 43 and their aligned belt wheels 22 and 23 rotatably mounted on thestub axles 19 and 20 forming a part of the striking Wheel 16. Handles45, 45 are secured to the housing 1t) to provide means by which the toolis manipulated.

Extending into one side of the striking wheel 16, to one side of itscenter, is a cored opening 46 which is round in cross section and whichhas a round plug 47 mounted within the cored opening 46 and which isheld in position by pins 48, 48 extending through the central webportion of the striking wheel 16 and having their ends upset to holdplug 47 in position. The plug 47 has a curved outer channelled endportion to conform to the curvature of the rim of the striking wheel 16and has a central bore 49 therein into which an inwardly extending ringportion 50 projects having an opening 51 centrally therethrough forpurposes hereinafter described.

From the opposite side ot the wheel 16 a broached opening 52 is providedwhich is preferably square in cross section, is slightly lesser in widthand height than is the diameter of the cored opening 46 whereby acircumferential shoulder 52a is formed on the wheel for purposeshereinafter described, and extends into and is aligned with the coredopening 46, and in which a slidably mounted hammer block 53 is mounted,the hammer block 53 having a circular end portion 54 on its inner end,and is adapted to be tted into and slidably mounted within the coredcircular opening 46, with the squared hammer block 53 being slidablymovable in the broached opening 52 into and out of impact position asmore fully described hereinafter.

The slidably mounted hammer block has a trunnion portion 55 formed onits inner end with an opening 56 therein and a cored opening 57extending longitudinally of the striking block 53 with a bolt 58 havinga head 59 formed thereon which is slidably mounted in the cored opening57 in the striking head 53 which bolt extends longitudinally ofthe coredopening 57 and has a compression spring 60 mounted thereon which abutsagainst the inner face of the head 59 at one of its ends and against awasher 61 at its opposite end. The washer 61 is held in position againstan annular shoulder 62 formed internally of the inturned end of thetrunnion 55 which bolt 58 extends through the opening 56 in the trunnion55 and through a split bushing 63 which is mounted in the opening 51 inthe annular portion Sti. A head 64 is formed on the inner end of thebolt 58 to prevent its retraction because of the expansive force of thespring 60 which spring 60 normally holds the striking block 53 inposition as shown in FIG. 1 of the drawings until thrown out intostriking position by centrifugal force generated by the striking Wheel16 by the rotative force imparted to it through the springs 28 and 29,belt wheels 22 and 23 and the motor acting through the gears 39 and 40and the belt wheels 43, 43 connected by the belts 44, 44 to the wheels22 and 23. The outward travel of the hammer block 53 is limited by theengagement of the circular end portion 54 against the shoulder 52a andthe inward movement by engagement of the same circular end portionagainst the end of the plug 47.

The hammer block 53 is inserted into the broached opening 52 byinserting it through the cored opening 46, and the plug 47 is thenplaced in position in the cored opening 46 and secured in place to thestriking wheel 16 by riveting or otherwise securing the pins 4S, 48 inposition. The bolt 58, the spring 66 and the washer 61, can then beassembled and the bolt 58 inserted through the opening 57 in the hammerblock 53 and through the split bushing 63 which has been previouslyplaced in position. The bolt 58 is pushed into position so that the endprojects through the bushing 63, with the spring 60 being compressed,whereupon the end of the bolt 58 is upset thereby forming the head 64thereon which prevents the bolt from being retracted by the expansiveforce of the spring 66. As this operation is performed the hammer block53 is pushed inward by the spring 60 until the circular end portion 54of the hammer block 53 is against the end of the plug 47 with thetrunnion 5S extending into the inner end of the bore 49 in whichposition the spring 60 is compressed only a slight amount therebyholding the hammer block 53 in retracted position until forced outwardinto striking position by centrifugal force imparted to it by reason ofthe rapid rotation of the striking wheel16.

An anvil guide 65 is provided having a rib 66 thereon which is securedto the housing 10 by means of bolts 67, 67 which pass through holes inthe rib 66 on the guide 65 and within which an anvil 66 is mounted, theupper end of which extends into the peripheral channel 18 on thestriking Wheel 16, and has a head portion 69 thereon on which shouldersare formed which engage against the guide 65 which acts as a limit stopto the upward movement of the anvil 68 to insure that the anvil 63 is inproper striking position relative to the hammer block 53 as shown inFIG. 3 of the drawings. A tool holder i0 is provided which is secured tothe lower end of the frame 1t) by the bolts 63, 63 having springs 71, 71thereon with a chisel 72 mounted therein with the upper end coming intonormal contact with the lower end of the anvil 68- and resiliently heldin contact therewith by the springs 71, 71. A latch 73 is providedwhereby the chisel 72 is held in position against the anvil 68 ifdesired and which can be released to allow downward movement of thechisel '72 when the tool is placed in operation. This entire arrangementof the tool holder is common to the mounting of chisels and tools oflike character in air hammers.

To operate the tool, power is applied to the motor mounted in thehousing 11, which power rotates the gears 39 and 4t) which in turnrotate the belt wheels 41 and 42 in a counter-clockwise direction asviewed in FIGS. 1 and 3 of the drawings, which belt wheels 41 and 42cause the rotation of the Wheels 22 and 23 on the axles 19 and 20 whichrotative force of the wheels 22 and 23 is communicated to the strikingwheel 16 through the springs 28 and 29 rotating this wheel in acounter-clockwise direction with the wheel being free to rotate becausethe hammer block 53 is held in the broached opening by the spring 60within the periphery of the striking Wheel 16 during the staticcondition of the device. As the speed of rotation of the striking Wheel16 increases, centrifugal force will cause the hammer block 53 to moveoutward overcoming the force of the spring 66 until its end portion 54reaches the shoulder 52ab at the inner end of the cored opening 46 andfar enough out of the rim of the wheel to squarely engage the anvil 68.As the blow is delivered to the anvil 68 there is a momentaryinterruption of the rotation of the striking wheel 16 with a slightrebounding of the striking wheel 16 in a reverse direction at whichpoint the striking wheel is static and the spring 60 snaps the hammerblock 53 back into the striking wheel 16 in the position shown in FIG. 1of the drawings so that the outer end is free of the anvil and theportion 54 is in abutting engagement with the plug 47 which acts as astop to the inward travel of the hammer block 53. In the meantime, thebelt wheels 22 and 23 are continuing to rotate, thereby exerting atorsion force iirst to the outer coils of the springs Z8 and 29 and ineffect Winding these springs about the hub portions 26, 26 of the beltwheels 22 and 23 and which springs, as soon as the hammer block iswithdrawn, exert a torsion pull to such an extent,

to accelerate its rotative speed very rapidly until by the time it hasmade a half to three quarters of a revolution its. speed of travelequals the speed of travel of the belt wheels 22 and 23. As the speed ofrotation of the striking wheel 16 accelerates, the centrifugal forcecreated by the rapid rotation of the striking wheel 16 causes the hammerblock to move outward to the limit of its travel or until its enlargedportion 5d engages against the wall of the wheel 16 at the end of thebreached channel, in which position the block is out far enough so thatit engages upon and delivers the blow to the entire face of the anvil63. As the hammer strikes the anvil, centrifugal force is no longerpresent and the hammer block is withdrawn into the striking wheel 16.

As hereinabove described, the springs 23 and 29 are fashioned in two.segments which enables, the use of very long wire and which enables agreat deal of tension to be placed into the spring which is distributedthrough the long wire section of the spring thereby distributing thetension to a greater extent than if the shorter length of spring wereused and also prevents an excess of tension from being present in anyarea of the spring thereby adding to the long life of the springs andthe prevention of metal fatigue arising in the springs resulting inbreakage thereof in service.

It will be noted that the striking block is mounted to one side of thecenter of the striking wheel and toward the outer periphery of thestriking Wheel which position assists in the development of thenecessary centrifugal force by the rotation of the striking Wheel toquickly and effectively throw the hammer block outward in the peripheryof the striking wheel to place the striking block into position todeliver a blow on the anvil and also, that the striking force of thestriking block upon the anvil is wholly transmitted to the strikingwheel because of thel engagement of the rim portion of the strikingwheel with the striking block so the striking block is not subject tothe stresses of the hammer blows but is absorbed by the striking wheel.

While l have described more or less precisely the method employed andthe apparatus used therewith, I do not wish to be understood as limitingmyself thereto, as I contemplate changes in form andv the proportion ofparts and the substitution of equivalents as circumstances may suggestor render expedient without departing from the spirit or scope of myinvention.

What is claimed is:

l. An impact tool comprising in combination a frame, a striking wheelmounted thereon having a peripheral opening therein, a hammer blockhaving an opening longitudinally thereof slidably mounted in the openingin the said wheel, a plug ixed to the striking Wheel at one end of thesaid peripheral opening, a bolt in the said plug extending into thelongitudinal opening in the hammer block, a spring on the said boltwithin the longitudinal opening in the hammer block normally biasing thesaid hammer block inwardly of the said wheel, a power driven wheelmounted upon a common axis with said striking wheel and a spring securedat one of its ends to the striking wheel adjacent its outer peripheryand at its other end to the power driven wheel also adjacent its outerperiphery.

2. An impact tool comprising in combination a frame, a striking wheelsupported by an axle and having a peripheral opening therein, a powerdriven wheel mounted upon the axle and rotatable thereon, a spiralspring secured at one of its ends to the striking wheel adjacent itsouter periphery and connected at its other end to the power driven wheeladjacent its outer periphery, a hammer block having an openinglongitudinally thereof slidably mounted in the peripheral opening in thesaid wheel, a plug having an enlarged inner end portion in the saidopening at one of its ends, a connecting member mounted in said plug andextending into the longitudinal opening in the hammer block having headsthereon at each of its ends and a compression spring on said connectingmember in abutting engagement at one of its ends with the end wall ofthe hammer block and at its other end with the head of the saidconnecting member whereby the said hammer block is biased inwardly ofthe wheel.

3. An impact tool comprising in combination a frame, a striking wheelsupported by an axle and having a peripheral opening therein extendingthrough the Wheel from edge toV edge at one side of the center of thewheel, a power driven Wheel mounted upon the axle and rotatable thereon,a spiral spring secured at one of its end to the striking wheel adjacentits outer periphery and connected at its other end to the power drivenwheel adjacent its outer periphery, a hammer block having an openinglongitudinally thereof slidably mounted in the peripheral opening in thesaid wheel, a plug having an enlarged inner end portion in the saidopening at one of its ends, a connecting member mounted in said plug andextending intothe longitudinal opening in the hammer block having headsthereon at each of its ends and a compression spring on said connectingmember in abutting` engagement at one of its ends with the end wall ofthe hammer block and at its other end with the head of the saidconnecting member whereby the hammer block is biased inwardlyr of thestriking wheel.

4. An impact tool comprisingin combination a frame, a striking wheelsupported by stub axles mounted on the said frame having an openingtherethrough from edge to edge, the said opening having diiferent crosssectional areas whereby an abutment is formed in the said Wheel, a powerdriven wheel rotatably mounted on one of said axles, a spiral springnested between the said wheels, one end of which spring is secured tothe power driven wheel near its outer edge and the other end' of thespring secured to the striking wheel adjacent its outer edge, a plug inthe larger sized opening secured to the said wheel terminating short ofthe said abutment, a slidably mounted hammer block mounted in theopening in the said wheel having an enlarged head portion extending intothe larger sized portion of the opening, a bolt mounted in the saidplug, and extending into the longitudinal opening in the hammer block,and a spring on the said bolt in abutting engagement at one of its endswith the end of the hammer block and the head of the bolt at its otherend whereby the hammer block is normally biased inwardly of the strikingWheel, the plug and the abutment forming limit stops to the inward andoutward movement of the said hammer block.

5. An impact tool comprising in combination a frame, a striking wheelsupported by stub axles thereon and having a peripheral opening thereinextending from edge to edge of the wheel, one portion of the openingbeing larger in cross-sectional area than the other, whereby an annularshoulder is formed upon the wheel, a power driven wheel rotatablymounted on one of the stub axles, a spiral spring nested between thestriking wheel and the power driven wheel having one of its ends securedto the power driven wheel adjacent its outer periphery and the other endsecured to the said striking wheel adjacent its outer periphery, ahammer block having an opening longitudinally thereof slidably mountedin the said peripheral opening having an enlarged end portion mounted inthe larger portion of the peripheral opening, a plug secured to the saidwheel forming a closure member for the peripheral opening at one of itsends, a bolt in the said plug having head portions thereon and extendinginto the hammer block and a spring on said bolt in engagement with oneof the heads on the said bolt and the hammer block normally biasing thehammer block inwardly of the said striking wheel, the shoulder on thewheel forming an outward limit stop to the movement of the hammer blockand the plug forming a limit stop to the inward movement of the saidhammer block.

6. An impact tool comprising in combination a frame, a striking wheelhaving a central web portion, a rim portion, and stub axles integrallyformed with the said web portion, mounted in the frame, a power Wheelrotatably mounted upon one of said axles, a spiral spring nested betweenthe striking wheel and the said power wheel having one of its endsconnected to the said power wheel adjacent its rim land connected at itsother end to the said striking wheel adjacent its rim portion, the saidstriking wheel having an opening thereacross at one side of its centerthe said opening at one end being larger than the other, the smallerportion being rectangular in shape and having a shoulder formed in theweb of the wheel, a hammer block slidably mounted in the smaller portionof the said opening and having an inner end portion extending into thelarger portion of the opening in the said wheel, a plug secured to thewheel forming a closure member for the larger portion of the saidopening and spaced from the shoulder on the web adjacent the smallportion of the opening in the web of the wheel whereby a chamber isformed in the web within which the inner end portion of the hammer blockextends, a bolt in said plug extending into the opening in the hammerblock and a spring on the said bolt in engagement with the head thereonand the end of the hammer block biasing the hammer block inwardly of thesaid striking wheel, y

7. An impact tool comprising in combination a frame, a striking wheelhavinga peripheral opening therein at one side of its center and havinga stub axle on each side thereof, power wheels rotatably mounted on eachof the said axles, spiral springs nested between the striking wheel andthe power wheel at each of its sides, one end of each of the saidsprings being secured to the power wheel adjacent its outer edge, theother end of each of said springs being secured to a power wheeladjacent its outer edge, a plug closing one end of the peripheralopening in its end opposite the plug, the hammer block having a centralopening therein, a bolt having head portions at each of its ends mountedin the said plug and extending into the central opening in the hammerblock and a spring on the said bolt in abutting engagement with the bolthead portions at one of its ends and with the said hammer block at itsopposite end and biasing the hammer block inwardly of the said wheel.

8. An impact tool comprising in combination a frame,

a striking wheel supported by an axle and having a peripheral openingtherein, a power driven wheel mounted upon the axle and rotatablethereon, a spiral spring secured at one of its ends to the strikingwheel adjacent its outer periphery and connected at its other end to thepower driven wheel adjacent its outer periphery, a hammer block slidablymounted in the peripheral opening at one end thereof in the said wheel,a plug secured to the said wheel forming a closure member for theperipheral opening at its side opposite the hammer block and a springconnected with the hammer block and the plug whereby the said hammerblock is withdrawn within the periphery of the wheel after delivery ofits stroke.

9. An impact tool comprising in combination a frame, a striking wheelhaving a central web portion and having an opening thereacross at oneside of its center, the said opening being of larger area at one of itsends than at the other, the smaller portion of the opening beingrectangular in shape, and having a shoulder formed thereon intermediateits ends, a power wheel rotating upon the same axis as the strikingwheel, a coiled spring nested between the striking and power wheelshaving one of its ends connected to the power wheel and its other end tothe striking wheel, a hammer block having a rectangular portion slidablymounted in the larger area of the said opening and having an enlargedhead portion in its inner end, a xed plug secured to the said wheel as aclosure member for the opening at one of its sides and a springconnected to the said plug and to the striking hammer normally tendingto hold the striking member within the periphery of the wheel, theenlarged portion of the hammer block engaging the shoulder as a limitstop to its outward movement and engaging the plug as a limit stop toits inward movement.

References Cited in the file of this patent UNITED STATES PATENTS1,598,088 Knowlson et al Aug. 31, 1926 1,598,091 Larocca Aug. 31, 19261,887,980 Martin Nov. 15, 1932 2,655,911 Van Russum et al. Oct. 20, 19532,888,246 Sieber May 26, 1959

1. AN IMPACT TOOL COMPRISING IN COMBINATION A FRAME, A STRIKING WHEELMOUNTED THEREON HAVING A PERIPHERAL OPENING THEREIN, A HAMMER BLOCKHAVING AN OPENING LONGITUDINALLY THEREOF SLIDABLY MOUNTED IN THE OPENINGIN THE SAID WHEEL, A PLUG FIXED TO THE STRIKING WHEEL AT ONE END OF THESAID PERIPHERAL OPENING, A BOLT IN THE SAID PLUG EXTENDING INTO THELONGITUDINAL OPENING IN THE HAMMER BLOCK, A SPRING ON THE SAID BOLTWITHIN THE LONGITUDINAL OPENING IN THE HAMMER BLOCK NORMALLY BIASING THESAID HAMMER BLOCK INWARDLY OF THE SAID WHEEL, A POWER DRIVEN WHEELMOUNTED UPON A COMMON AXIS WITH SAID STRIKING WHEEL AND A SPRING SECUREDAT ONE OF ITS ENDS TO THE STRIKING WHEEL ADJACENT ITS OUTER PERIPHERYAND AT ITS OTHER END TO THE POWER DRIVEN WHEEL ALSO ADJACENT ITS OUTERPERIPHERY.